Double Wall PCHE With Intermediate Third Plate For Leak Detection
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Solution Overview
Problem
Printed circuit heat exchangers face challenges in containing and detecting leaks of highly explosive fuels like LNG, LPG, and LH2, as they lack a robust secondary barrier mechanism to prevent direct contact between fluids and detect potential leaks effectively.
Innovation Solution
Incorporating intermediate third plates with communicating holes between the first and second fluid plates, allowing a third fluid (inert gas or good heat conductor) to isolate and redirect any leaks through leakage channels to a common exit point for detection, using diffusion bonding to form a secure heat exchanger assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a double wall structure with intermediate third plates is used to isolate and detect leaks, then safety and leak detection capability are improved, but device complexity increases
Solution Approach 1:
The intermediate third plate with leakage channels is nested between the first and second fluid plates, creating a hierarchical structure where the third plate is contained within the assembly of the first and second plates. This nesting approach allows the leak detection system to be integrated within the existing heat exchanger structure rather than adding external components, thereby improving safety while limiting the increase in device complexity.
Solution Approach 2:
The intermediate third plate acts as an intermediary element between the first and second fluid plates. It provides a dedicated pathway (leakage channels) for detecting leaks from either fluid plate without allowing direct contact between the first and second fluids. This mediator approach enables safe leak detection while maintaining the functional integrity of the heat exchanger.
2Measurement precision
If communicating holes are added to allow fluid passage through plates, then leak detection capability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The communicating holes in the intermediate third plate serve multiple functions: they allow the third fluid to flow through the plate, enable detection of leaks from both the first and second fluid plates, and provide structural integration between the different plates. This multi-functionality reduces the need for separate detection mechanisms, thereby improving leak detection capability while potentially reducing overall manufacturing complexity.
Solution Approach 2:
The leakage detection function is merged with the fluid passage function in the intermediate third plate. The same communicating holes that allow third fluid to flow through the plate also serve as the pathway for detecting leaks from the first and second fluids. This merging of functions eliminates the need for separate detection channels, improving detection capability while simplifying the manufacturing process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design effectively isolates and detects leaks within the heat exchanger, ensuring containment and safe disposal of leaking fluids, enhancing safety by preventing direct contact between explosive fluids and enabling real-time leakage monitoring.
Implementation Method 1
the use of a pair of intermediate third plates placed below and above the first fluid plate, thereby completely isolating the first fluid from the second fluid
Implementation Method 2
The first, second, & third plates are designed with communicating holes that allow for fluid passage through the entire height of the heat exchanger block
Implementation Method 3
the micro-channels are arranged to receive the leaking fluid from the first or second channels and permit flow of the leaking fluid to the leakage channels
Implementation Method 4
The first and second plates are then placed alternately on top of each other, until the required number of plates is reached to form a heat exchanger element, at which point the plates are bonded together using the process of diffusion bonding
Data Source
Figure 1~2
Figure 3
AI summary
The present invention discloses a double wall printed circuit heat exchanger (PCHE), whereby etched plates are diffusion bonded together in order to form paths for a first, second, and third fluid. The third fluid being the transport fluid for any leakage of the first or second fluids, whereby the leakage can then be detected on exiting the assembled body of the heat exchanger.